An Ohio grand jury has charged Sister Marguerite Kloos, 54, who cast a second ballot for a deceased friend in the 2012 presidential election, with one felony count of illegal voting, according to a statement released Monday by Hamilton County Prosecutor Joseph T. Deters. Kloos, who could face up to 18 months in prison, resigned last week from her position as a dean of a Cincinnati college.

Kloos was accused of casting an absentee ballot for another nun -- Sister Rose Marie Hewitt -- who died before Election Day.

"This woman who died was a dear, dear friend who lived with [Kloos] for more than 25 years," Kohnen told ABCNews.com. "The woman died unexpectedly. That really left my client wracked with grief. Sister Kloos' normally impeccable judgment was impaired, and she sought to see her best friend's wishes through by casting her ballot as if she were alive."

Kloos is accused of signing Hewitt's name and returning her ballot to the Hamilton County Board of Elections. Because her lawyer confirmed that Kloos intended to plead guilty, she faced a preliminary hearing, rather than an indictment, by the grand jury.

Jill Eichhorn, a representative of the College of Mount St. Joseph, where Kloos had been dean of the Division of Arts and Humanities since 2009, confirmed to ABCNews.com that the deceased Hewitt was the person whom Kloos had cast a ballot for.

The college released a statement confirming Kloos' resignation.

"As a valued member of the Mount St. Joseph community, our thoughts are with her during this difficult time. We respect her privacy and will not comment further on this matter at this time," read the statement.

Deters, the Hamilton County prosecutor, highlighted the seriousness of voter fraud in his statement.

"Elections are a serious business and the foundation of our democracy," Deters said. "Every vote is important, and every voter and candidate needs to have faith in our system. The charges today should let people know that we take this seriously. This is not North Korea."

Two other residents of Hamilton County are also facing charges of voter fraud. Russell Glassop, 75, and Melowese Richardson, 54, face one- and eight-count indictments of illegal voting, respectively, according to Deters' statement.

Glassop is charged with voting on behalf of his deceased wife, while Richardson, a long-time poll worker, is accused of voting twice on her own behalf and on behalf of other people in various elections.

Three additional cases of possible voter fraud are still under investigation in the county.